mount.c revision 92882 
1/*-
2 * Copyright (c) 1980, 1989, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1980, 1989, 1993, 1994\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41#if 0
42static char sccsid[] = "@(#)mount.c	8.25 (Berkeley) 5/8/95";
43#endif
44static const char rcsid[] =
45  "$FreeBSD: head/sbin/mount/mount.c 92882 2002-03-21 13:14:21Z imp $";
46#endif /* not lint */
47
48#include <sys/param.h>
49#include <sys/mount.h>
50#include <sys/stat.h>
51#include <sys/wait.h>
52
53#include <err.h>
54#include <errno.h>
55#include <fstab.h>
56#include <pwd.h>
57#include <signal.h>
58#include <stdio.h>
59#include <stdlib.h>
60#include <string.h>
61#include <unistd.h>
62
63#include "extern.h"
64#include "mntopts.h"
65#include "pathnames.h"
66
67/* `meta' options */
68#define MOUNT_META_OPTION_FSTAB		"fstab"
69#define MOUNT_META_OPTION_CURRENT	"current"
70
71int debug, fstab_style, verbose;
72
73char   *catopt(char *, const char *);
74struct statfs *getmntpt(const char *);
75int	hasopt(const char *, const char *);
76int	ismounted(struct fstab *, struct statfs *, int);
77int	isremountable(const char *);
78void	mangle(char *, int *, const char **);
79char   *update_options(char *, char *, int);
80int	mountfs(const char *, const char *, const char *,
81			int, const char *, const char *);
82void	remopt(char *, const char *);
83void	prmount(struct statfs *);
84void	putfsent(const struct statfs *);
85void	usage(void);
86char   *flags2opts(int);
87
88/* Map from mount options to printable formats. */
89static struct opt {
90	int o_opt;
91	const char *o_name;
92} optnames[] = {
93	{ MNT_ASYNC,		"asynchronous" },
94	{ MNT_EXPORTED,		"NFS exported" },
95	{ MNT_LOCAL,		"local" },
96	{ MNT_NOATIME,		"noatime" },
97	{ MNT_NODEV,		"nodev" },
98	{ MNT_NOEXEC,		"noexec" },
99	{ MNT_NOSUID,		"nosuid" },
100	{ MNT_NOSYMFOLLOW,	"nosymfollow" },
101	{ MNT_QUOTA,		"with quotas" },
102	{ MNT_RDONLY,		"read-only" },
103	{ MNT_SYNCHRONOUS,	"synchronous" },
104	{ MNT_UNION,		"union" },
105	{ MNT_NOCLUSTERR,	"noclusterr" },
106	{ MNT_NOCLUSTERW,	"noclusterw" },
107	{ MNT_SUIDDIR,		"suiddir" },
108	{ MNT_SOFTDEP,		"soft-updates" },
109	{ 0, NULL }
110};
111
112/*
113 * List of VFS types that can be remounted without becoming mounted on top
114 * of each other.
115 * XXX Is this list correct?
116 */
117static const char *
118remountable_fs_names[] = {
119	"ufs", "ffs", "ext2fs",
120	0
121};
122
123int
124main(argc, argv)
125	int argc;
126	char * const argv[];
127{
128	const char *mntfromname, **vfslist, *vfstype;
129	struct fstab *fs;
130	struct statfs *mntbuf;
131	FILE *mountdfp;
132	pid_t pid;
133	int all, ch, i, init_flags, mntsize, rval, have_fstab;
134	char *options;
135
136	all = init_flags = 0;
137	options = NULL;
138	vfslist = NULL;
139	vfstype = "ufs";
140	while ((ch = getopt(argc, argv, "adfo:prwt:uv")) != -1)
141		switch (ch) {
142		case 'a':
143			all = 1;
144			break;
145		case 'd':
146			debug = 1;
147			break;
148		case 'f':
149			init_flags |= MNT_FORCE;
150			break;
151		case 'o':
152			if (*optarg)
153				options = catopt(options, optarg);
154			break;
155		case 'p':
156			fstab_style = 1;
157			verbose = 1;
158			break;
159		case 'r':
160			options = catopt(options, "ro");
161			break;
162		case 't':
163			if (vfslist != NULL)
164				errx(1, "only one -t option may be specified");
165			vfslist = makevfslist(optarg);
166			vfstype = optarg;
167			break;
168		case 'u':
169			init_flags |= MNT_UPDATE;
170			break;
171		case 'v':
172			verbose = 1;
173			break;
174		case 'w':
175			options = catopt(options, "noro");
176			break;
177		case '?':
178		default:
179			usage();
180			/* NOTREACHED */
181		}
182	argc -= optind;
183	argv += optind;
184
185#define	BADTYPE(type)							\
186	(strcmp(type, FSTAB_RO) &&					\
187	    strcmp(type, FSTAB_RW) && strcmp(type, FSTAB_RQ))
188
189	rval = 0;
190	switch (argc) {
191	case 0:
192		if ((mntsize = getmntinfo(&mntbuf, MNT_NOWAIT)) == 0)
193			err(1, "getmntinfo");
194		if (all) {
195			while ((fs = getfsent()) != NULL) {
196				if (BADTYPE(fs->fs_type))
197					continue;
198				if (checkvfsname(fs->fs_vfstype, vfslist))
199					continue;
200				if (hasopt(fs->fs_mntops, "noauto"))
201					continue;
202				if (!(init_flags & MNT_UPDATE) &&
203				    ismounted(fs, mntbuf, mntsize))
204					continue;
205				if (mountfs(fs->fs_vfstype, fs->fs_spec,
206				    fs->fs_file, init_flags, options,
207				    fs->fs_mntops))
208					rval = 1;
209			}
210		} else if (fstab_style) {
211			for (i = 0; i < mntsize; i++) {
212				if (checkvfsname(mntbuf[i].f_fstypename, vfslist))
213					continue;
214				putfsent(&mntbuf[i]);
215			}
216		} else {
217			for (i = 0; i < mntsize; i++) {
218				if (checkvfsname(mntbuf[i].f_fstypename,
219				    vfslist))
220					continue;
221				prmount(&mntbuf[i]);
222			}
223		}
224		exit(rval);
225	case 1:
226		if (vfslist != NULL)
227			usage();
228
229		if (init_flags & MNT_UPDATE) {
230			mntfromname = NULL;
231			have_fstab = 0;
232			if ((mntbuf = getmntpt(*argv)) == NULL)
233				errx(1, "not currently mounted %s", *argv);
234			/*
235			 * Only get the mntflags from fstab if both mntpoint
236			 * and mntspec are identical. Also handle the special
237			 * case where just '/' is mounted and 'spec' is not
238			 * identical with the one from fstab ('/dev' is missing
239			 * in the spec-string at boot-time).
240			 */
241			if ((fs = getfsfile(mntbuf->f_mntonname)) != NULL) {
242				if (strcmp(fs->fs_spec,
243				    mntbuf->f_mntfromname) == 0 &&
244				    strcmp(fs->fs_file,
245				    mntbuf->f_mntonname) == 0) {
246					have_fstab = 1;
247					mntfromname = mntbuf->f_mntfromname;
248				} else if (argv[0][0] == '/' &&
249				    argv[0][1] == '\0') {
250					fs = getfsfile("/");
251					have_fstab = 1;
252					mntfromname = fs->fs_spec;
253				}
254			}
255			if (have_fstab) {
256				options = update_options(options, fs->fs_mntops,
257				    mntbuf->f_flags);
258			} else {
259				mntfromname = mntbuf->f_mntfromname;
260				options = update_options(options, NULL,
261				    mntbuf->f_flags);
262			}
263			rval = mountfs(mntbuf->f_fstypename, mntfromname,
264			    mntbuf->f_mntonname, init_flags, options, 0);
265			break;
266		}
267		rmslashes(*argv, *argv);
268		if ((fs = getfsfile(*argv)) == NULL &&
269		    (fs = getfsspec(*argv)) == NULL)
270			errx(1, "%s: unknown special file or file system",
271			    *argv);
272		if (BADTYPE(fs->fs_type))
273			errx(1, "%s has unknown file system type",
274			    *argv);
275		rval = mountfs(fs->fs_vfstype, fs->fs_spec, fs->fs_file,
276		    init_flags, options, fs->fs_mntops);
277		break;
278	case 2:
279		/*
280		 * If -t flag has not been specified, the path cannot be
281		 * found, spec contains either a ':' or a '@', and the
282		 * spec is not a file with those characters, then assume
283		 * that an NFS filesystem is being specified ala Sun.
284		 */
285		if (vfslist == NULL && strpbrk(argv[0], ":@") != NULL &&
286		    access(argv[0], 0) == -1)
287			vfstype = "nfs";
288		rval = mountfs(vfstype,
289		    argv[0], argv[1], init_flags, options, NULL);
290		break;
291	default:
292		usage();
293		/* NOTREACHED */
294	}
295
296	/*
297	 * If the mount was successfully, and done by root, tell mountd the
298	 * good news.  Pid checks are probably unnecessary, but don't hurt.
299	 */
300	if (rval == 0 && getuid() == 0 &&
301	    (mountdfp = fopen(_PATH_MOUNTDPID, "r")) != NULL) {
302		if (fscanf(mountdfp, "%d", &pid) == 1 &&
303		     pid > 0 && kill(pid, SIGHUP) == -1 && errno != ESRCH)
304			err(1, "signal mountd");
305		(void)fclose(mountdfp);
306	}
307
308	exit(rval);
309}
310
311int
312ismounted(fs, mntbuf, mntsize)
313	struct fstab *fs;
314	struct statfs *mntbuf;
315	int mntsize;
316{
317	int i;
318
319	if (fs->fs_file[0] == '/' && fs->fs_file[1] == '\0')
320		/* the root file system can always be remounted */
321		return (0);
322
323	for (i = mntsize - 1; i >= 0; --i)
324		if (strcmp(fs->fs_file, mntbuf[i].f_mntonname) == 0 &&
325		    (!isremountable(fs->fs_vfstype) ||
326		     strcmp(fs->fs_spec, mntbuf[i].f_mntfromname) == 0))
327			return (1);
328	return (0);
329}
330
331int
332isremountable(vfsname)
333	const char *vfsname;
334{
335	const char **cp;
336
337	for (cp = remountable_fs_names; *cp; cp++)
338		if (strcmp(*cp, vfsname) == 0)
339			return (1);
340	return (0);
341}
342
343int
344hasopt(mntopts, option)
345	const char *mntopts, *option;
346{
347	int negative, found;
348	char *opt, *optbuf;
349
350	if (option[0] == 'n' && option[1] == 'o') {
351		negative = 1;
352		option += 2;
353	} else
354		negative = 0;
355	optbuf = strdup(mntopts);
356	found = 0;
357	for (opt = optbuf; (opt = strtok(opt, ",")) != NULL; opt = NULL) {
358		if (opt[0] == 'n' && opt[1] == 'o') {
359			if (!strcasecmp(opt + 2, option))
360				found = negative;
361		} else if (!strcasecmp(opt, option))
362			found = !negative;
363	}
364	free(optbuf);
365	return (found);
366}
367
368int
369mountfs(vfstype, spec, name, flags, options, mntopts)
370	const char *vfstype, *spec, *name, *options, *mntopts;
371	int flags;
372{
373	/* List of directories containing mount_xxx subcommands. */
374	static const char *edirs[] = {
375		_PATH_SBIN,
376		_PATH_USRSBIN,
377		NULL
378	};
379	const char *argv[100], **edir;
380	struct statfs sf;
381	pid_t pid;
382	int argc, i, status;
383	char *optbuf, execname[MAXPATHLEN + 1], mntpath[MAXPATHLEN];
384
385#if __GNUC__
386	(void)&optbuf;
387	(void)&name;
388#endif
389
390	/* resolve the mountpoint with realpath(3) */
391	(void)checkpath(name, mntpath);
392	name = mntpath;
393
394	if (mntopts == NULL)
395		mntopts = "";
396	if (options == NULL) {
397		if (*mntopts == '\0') {
398			options = "rw";
399		} else {
400			options = mntopts;
401			mntopts = "";
402		}
403	}
404	optbuf = catopt(strdup(mntopts), options);
405
406	if (strcmp(name, "/") == 0)
407		flags |= MNT_UPDATE;
408	if (flags & MNT_FORCE)
409		optbuf = catopt(optbuf, "force");
410	if (flags & MNT_RDONLY)
411		optbuf = catopt(optbuf, "ro");
412	/*
413	 * XXX
414	 * The mount_mfs (newfs) command uses -o to select the
415	 * optimization mode.  We don't pass the default "-o rw"
416	 * for that reason.
417	 */
418	if (flags & MNT_UPDATE)
419		optbuf = catopt(optbuf, "update");
420
421	/* Compatibility glue. */
422	if (strcmp(vfstype, "msdos") == 0)
423		vfstype = "msdosfs";
424
425	argc = 0;
426	argv[argc++] = vfstype;
427	mangle(optbuf, &argc, argv);
428	argv[argc++] = spec;
429	argv[argc++] = name;
430	argv[argc] = NULL;
431
432	if (debug) {
433		(void)printf("exec: mount_%s", vfstype);
434		for (i = 1; i < argc; i++)
435			(void)printf(" %s", argv[i]);
436		(void)printf("\n");
437		return (0);
438	}
439
440	switch (pid = fork()) {
441	case -1:				/* Error. */
442		warn("fork");
443		free(optbuf);
444		return (1);
445	case 0:					/* Child. */
446		if (strcmp(vfstype, "ufs") == 0)
447			exit(mount_ufs(argc, (char * const *) argv));
448
449		/* Go find an executable. */
450		for (edir = edirs; *edir; edir++) {
451			(void)snprintf(execname,
452			    sizeof(execname), "%s/mount_%s", *edir, vfstype);
453			execv(execname, (char * const *)argv);
454		}
455		if (errno == ENOENT) {
456			int len = 0;
457			char *cp;
458			for (edir = edirs; *edir; edir++)
459				len += strlen(*edir) + 2;	/* ", " */
460			if ((cp = malloc(len)) == NULL)
461				errx(1, "malloc failed");
462			cp[0] = '\0';
463			for (edir = edirs; *edir; edir++) {
464				strcat(cp, *edir);
465				if (edir[1] != NULL)
466					strcat(cp, ", ");
467			}
468			warn("exec mount_%s not found in %s", vfstype, cp);
469		}
470		exit(1);
471		/* NOTREACHED */
472	default:				/* Parent. */
473		free(optbuf);
474
475		if (waitpid(pid, &status, 0) < 0) {
476			warn("waitpid");
477			return (1);
478		}
479
480		if (WIFEXITED(status)) {
481			if (WEXITSTATUS(status) != 0)
482				return (WEXITSTATUS(status));
483		} else if (WIFSIGNALED(status)) {
484			warnx("%s: %s", name, sys_siglist[WTERMSIG(status)]);
485			return (1);
486		}
487
488		if (verbose) {
489			if (statfs(name, &sf) < 0) {
490				warn("statfs %s", name);
491				return (1);
492			}
493			if (fstab_style)
494				putfsent(&sf);
495			else
496				prmount(&sf);
497		}
498		break;
499	}
500
501	return (0);
502}
503
504void
505prmount(sfp)
506	struct statfs *sfp;
507{
508	int flags;
509	struct opt *o;
510	struct passwd *pw;
511
512	(void)printf("%s on %s (%s", sfp->f_mntfromname, sfp->f_mntonname,
513	    sfp->f_fstypename);
514
515	flags = sfp->f_flags & MNT_VISFLAGMASK;
516	for (o = optnames; flags && o->o_opt; o++)
517		if (flags & o->o_opt) {
518			(void)printf(", %s", o->o_name);
519			flags &= ~o->o_opt;
520		}
521	if (sfp->f_owner) {
522		(void)printf(", mounted by ");
523		if ((pw = getpwuid(sfp->f_owner)) != NULL)
524			(void)printf("%s", pw->pw_name);
525		else
526			(void)printf("%d", sfp->f_owner);
527	}
528	if (verbose) {
529		if (sfp->f_syncwrites != 0 || sfp->f_asyncwrites != 0)
530			(void)printf(", writes: sync %ld async %ld",
531			    sfp->f_syncwrites, sfp->f_asyncwrites);
532		if (sfp->f_syncreads != 0 || sfp->f_asyncreads != 0)
533			(void)printf(", reads: sync %ld async %ld",
534			    sfp->f_syncreads, sfp->f_asyncreads);
535	}
536	(void)printf(")\n");
537}
538
539struct statfs *
540getmntpt(name)
541	const char *name;
542{
543	struct statfs *mntbuf;
544	int i, mntsize;
545
546	mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
547	for (i = mntsize - 1; i >= 0; i--) {
548		if (strcmp(mntbuf[i].f_mntfromname, name) == 0 ||
549		    strcmp(mntbuf[i].f_mntonname, name) == 0)
550			return (&mntbuf[i]);
551	}
552	return (NULL);
553}
554
555char *
556catopt(s0, s1)
557	char *s0;
558	const char *s1;
559{
560	size_t i;
561	char *cp;
562
563	if (s1 == NULL || *s1 == '\0')
564		return s0;
565
566	if (s0 && *s0) {
567		i = strlen(s0) + strlen(s1) + 1 + 1;
568		if ((cp = malloc(i)) == NULL)
569			errx(1, "malloc failed");
570		(void)snprintf(cp, i, "%s,%s", s0, s1);
571	} else
572		cp = strdup(s1);
573
574	if (s0)
575		free(s0);
576	return (cp);
577}
578
579void
580mangle(options, argcp, argv)
581	char *options;
582	int *argcp;
583	const char **argv;
584{
585	char *p, *s;
586	int argc;
587
588	argc = *argcp;
589	for (s = options; (p = strsep(&s, ",")) != NULL;)
590		if (*p != '\0') {
591			if (*p == '-') {
592				argv[argc++] = p;
593				p = strchr(p, '=');
594				if (p) {
595					*p = '\0';
596					argv[argc++] = p+1;
597				}
598			} else if (strcmp(p, "rw") != 0) {
599				argv[argc++] = "-o";
600				argv[argc++] = p;
601			}
602		}
603
604	*argcp = argc;
605}
606
607
608char *
609update_options(opts, fstab, curflags)
610	char *opts;
611	char *fstab;
612	int curflags;
613{
614	char *o, *p;
615	char *cur;
616	char *expopt, *newopt, *tmpopt;
617
618	if (opts == NULL)
619		return strdup("");
620
621	/* remove meta options from list */
622	remopt(fstab, MOUNT_META_OPTION_FSTAB);
623	remopt(fstab, MOUNT_META_OPTION_CURRENT);
624	cur = flags2opts(curflags);
625
626	/*
627	 * Expand all meta-options passed to us first.
628	 */
629	expopt = NULL;
630	for (p = opts; (o = strsep(&p, ",")) != NULL;) {
631		if (strcmp(MOUNT_META_OPTION_FSTAB, o) == 0)
632			expopt = catopt(expopt, fstab);
633		else if (strcmp(MOUNT_META_OPTION_CURRENT, o) == 0)
634			expopt = catopt(expopt, cur);
635		else
636			expopt = catopt(expopt, o);
637	}
638	free(cur);
639	free(opts);
640
641	/*
642	 * Remove previous contradictory arguments. Given option "foo" we
643	 * remove all the "nofoo" options. Given "nofoo" we remove "nonofoo"
644	 * and "foo" - so we can deal with possible options like "notice".
645	 */
646	newopt = NULL;
647	for (p = expopt; (o = strsep(&p, ",")) != NULL;) {
648		if ((tmpopt = malloc( strlen(o) + 2 + 1 )) == NULL)
649			errx(1, "malloc failed");
650
651		strcpy(tmpopt, "no");
652		strcat(tmpopt, o);
653		remopt(newopt, tmpopt);
654		free(tmpopt);
655
656		if (strncmp("no", o, 2) == 0)
657			remopt(newopt, o+2);
658
659		newopt = catopt(newopt, o);
660	}
661	free(expopt);
662
663	return newopt;
664}
665
666void
667remopt(string, opt)
668	char *string;
669 	const char *opt;
670{
671	char *o, *p, *r;
672
673	if (string == NULL || *string == '\0' || opt == NULL || *opt == '\0')
674		return;
675
676	r = string;
677
678	for (p = string; (o = strsep(&p, ",")) != NULL;) {
679		if (strcmp(opt, o) != 0) {
680			if (*r == ',' && *o != '\0')
681				r++;
682			while ((*r++ = *o++) != '\0')
683			    ;
684			*--r = ',';
685		}
686	}
687	*r = '\0';
688}
689
690void
691usage()
692{
693
694	(void)fprintf(stderr, "%s\n%s\n%s\n",
695"usage: mount [-dfpruvw] [-o options] [-t ufs | external_type] special node",
696"       mount [-adfpruvw] [-t ufs | external_type]",
697"       mount [-dfpruvw] special | node");
698	exit(1);
699}
700
701void
702putfsent(ent)
703	const struct statfs *ent;
704{
705	struct fstab *fst;
706	char *opts;
707
708	opts = flags2opts(ent->f_flags);
709	printf("%s\t%s\t%s %s", ent->f_mntfromname, ent->f_mntonname,
710	    ent->f_fstypename, opts);
711	free(opts);
712
713	if ((fst = getfsspec(ent->f_mntfromname)))
714		printf("\t%u %u\n", fst->fs_freq, fst->fs_passno);
715	else if ((fst = getfsfile(ent->f_mntonname)))
716		printf("\t%u %u\n", fst->fs_freq, fst->fs_passno);
717	else if (strcmp(ent->f_fstypename, "ufs") == 0) {
718		if (strcmp(ent->f_mntonname, "/") == 0)
719			printf("\t1 1\n");
720		else
721			printf("\t2 2\n");
722	} else
723		printf("\t0 0\n");
724}
725
726
727char *
728flags2opts(flags)
729	int flags;
730{
731	char *res;
732
733	res = NULL;
734
735	res = catopt(res, (flags & MNT_RDONLY) ? "ro" : "rw");
736
737	if (flags & MNT_SYNCHRONOUS)	res = catopt(res, "sync");
738	if (flags & MNT_NOEXEC)		res = catopt(res, "noexec");
739	if (flags & MNT_NOSUID)		res = catopt(res, "nosuid");
740	if (flags & MNT_NODEV)		res = catopt(res, "nodev");
741	if (flags & MNT_UNION)		res = catopt(res, "union");
742	if (flags & MNT_ASYNC)		res = catopt(res, "async");
743	if (flags & MNT_NOATIME)	res = catopt(res, "noatime");
744	if (flags & MNT_NOCLUSTERR)	res = catopt(res, "noclusterr");
745	if (flags & MNT_NOCLUSTERW)	res = catopt(res, "noclusterw");
746	if (flags & MNT_NOSYMFOLLOW)	res = catopt(res, "nosymfollow");
747	if (flags & MNT_SUIDDIR)	res = catopt(res, "suiddir");
748
749	return res;
750}
751